Electrical precipitator



March 5, 1956 v E. v. HARLOW 2,737,259

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March 6, 1956 E. v. HARLOW 2,737,259

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United States Patent ELECTRICAL PRECIPITATOR Earl V. Harlow, Towson, Md., assignor to Koppers Company, Inc a corporation of Delaware Application January 18, 1954, Serial No. 404,615

6 Claims. (Cl. 183-7) The present invention relates to electrical precipitators and more particularly to electrode structure for use therein.

As steam generating plants, open-hearth furnaces and other industrial units have increased in size, it has become necessary to increase the size of the electrical precipitators which are utilized with these units to remove the fly ash or dust from efiluent' gases. Large precipitators require large sized electrode structures and this creates additional problems, since it is more difiicult to support the weight of such electrode structures, maintain them in fixed spaced relationship and yet avoid having the supporting structure interfere with the gas flow in the precipitator chamber.

One of the features of the present invention is to provide a collecting electrode structure in which a substantially unlimited area can be maintained in one plane.

Another feature of the present invention is to provide a collecting electrode structure which is light in Weight, making it readily susceptible to rapping operations.

Another feature of the present invention is to provide a collecting electrode structure which is etficient in construction, maintenance and operation.

Another feature of the present invention is to provide a collecting electrode structure that can be simply and quickly assembled.

Another feature of the present invention is to provide a collecting electrode structure wherein a substantially constant tension is maintained on the collecting electrode units.

Still another feature of the present invention is to provide a collecting electrode structure which reduces undesirable features of warping due to welding, machining and handling.

Still another feature of the present invention is to pro vide a collecting electrode structure wherein more effective electrical contact is obtained.

One inventive form of collecting electrode structurewhich satisfies all the above features has been disclosed in co-filed application, Serial No. 404,614 of even date herewith.

More particularly the present invention provides in an electrical precipitator having a precipitating chamber with a plurality of parallel spaced vertical discharge electrode units therein, a collecting electrode structure comprising a plurality of parallel spaced vertical collecting electrode units so arranged that each of said discharge electrode units is positioned substantially parallel to adjacent collecting electrode units; a plurality of suspension means, each connected to corresponding ends of said collecting electrode units whereby said units are vertically suspended within said precipitating chamber; and tensioning and aligning means adapted to hold said collecting electrode units under constant tension and to maintain said units in planes substantially parallel to each other.

It will be obvious to one skilled in the art to which this invention pertains that various changes can be made in the arrangement, form, construction and type of the various elements disclosed without departing from the scope or spirit of this invention.

Reference will now be made to the accompanying drawings which illustrate and exemplify an embodiment of the invention in a preferred type of construction.

Figure 1 represents a side view of an electrical precipitator, cut away to disclose the collecting electrode structure.

Figure 2 represents a front view of the electrical precipitator of Fig. 1, cut away to disclose the arrangement of the collecting and discharge units and one type of tensioning means for the collecting electrode units.

Figure 3 represents a partial front view of another type of tensioning means for collecting electrode units, the units comprising pocket style electrode panels.

Figure. 4 represents a sectional view of Fig. 3 taken along the line IVIV of Figure 3.

Figure 5 represents an enlarged partial view disclosing the linkage mechanism for the electrode panels of Figure 4.

Figure 6 represents a sectional view of Figure 5 taken along the line VIVI of Figure 5.

Referring to Figures 1 and 20f the drawings, precipitating chamber 2 is disclosed having a plurality of parallel spaced vertical discharge electrode units 4 suspended therein from the hanger bar assembly 6. This assembly is, in turn, suspended from hanger rods (not shown) positioned in the insulator housings 8. High tension wires (also not shown) lead to the insulator housings and a rapping mechanism 10 is connected to the hanger bar assembly 6 through rod 12. All of the structure described so far is well known in the art'and does not constitute a critical part of the present invention.

A collecting electrode structure comprising a plurality of parallel spaced vertical collecting electrode units 14 is so arranged that each of said discharge electrode units is positioned substantially parallel to adjacent collecting electrode units, the collecting electrode units being suspended from the chamber 2 by hanger rods 16. Each of the collecting electrode units 14 is divided into a plurality of separate panels 18, which panels are linked one to another by the linking members 20. By providing separate panels, erection costs and erection time are greatly reduced and problems of warping which accompany the use of one continuous unit are greatly minimized. Further, the use of separate panels renders the collecting electrodes more sensitive to light rapping. The penels, themselves. can be constructed like those disclosed in the co-filed application, Serial No. 404,614, with reinforcing strips along vertical edges and bead-rolled horizontal edges, vor, in anotheradvantageous embodiment of the invention, the panels can be of the pocket type as disclosed in Figures 3 to 6, hereinafter described.

Attached to each of the lower corners of each of the lowermost panels is sheave 22 and positioned below the corresponding lower corners of each of the lowermost panels are members 24, which can be channel members, which are fixed to the sides of precipitating chamber 2. Fixed to each of the members 24 are sheaves 26, each sheave being positioned below a lower corner of the discharge electrode units.

Ropes or cables 28, which can be of steel, connect the upper and lower row of sheaves in snake-like fashion. One end of each cable is anchored to the channel 24 as indicated at 30. At the opposite end of each cable is attached a counterweight 32. The cables and sheaves operate on the well-known principle of fixed and movable pulleys and, neglecting friction, the tension in each collecting electrode unit will be equal to twice the weight of the counterweight 32. It is to be understood that the number of collecting electrode units tensioned by one set of cable and sheaves can be varied to suit conditions,

The limiting factor is the friction in the sheaves which retard movement of the cables 28, when the electrode units and sheave and cable arrangements contract due :to cooling.

As shown in Figures 3 toiopocket style electrode panels 34, which 'are well known in the art, can be :used in order to :limit re-entrainment -of precipitatedmaterial-in the gas during rapping. The pocket panels are "linked together by linking members 29, which are connected t'oitheipancls .34 by bolt and inut=assemblie's 38. The2nuts are not made tight enough to bind the linkage, but are left loose to allow free alignment when the linkage is placed under tension. The nuts are tack welded as at -40 -to preventIrotation on the bolt 'due1to vibration.

In Figures 3 and 4, a spring tensionin'g device'is providedvin place-of the counterweight '32 disclosed in Figures .1 :and 2. One end of :the cable '28 is anchored to the member :24, as indicated by ithe reference numeral "41. The other end of ith'e'cable .is fixed to a threaded bolt 44, having a nut 46 threaded thereon. Abutt'ing against the nut =46 is a washer 48 and positioned between the washer 48 :and :the outerwall of the precipitating chamher 2, encircling the bolt 44, is a coil spring 50. .By

turning the nut 46, tension on 'the cable :28 can .b'e adjusted Within limits. The cable and sheaves of this advantageous embodiment of the :invention also operate on the well-known principle 'offixedaand movable pulleys,

and, neglecting friction, the .tensionin the collecting electrode units 14 will be equal *to twice the spring tension created by coil spring 50.

Finally it is tobe noted that the inventivefeatures disclosed herein can be applied to :discharge electrodes as Well as to collecting electrodes of an electrical precipi- 'tator.

The invention claimed :is: 1. In :an electrical precipitatorhaving La precipitating chamber with a plurality of parallel spaced vertical discharge electrode units therein, a collecting electrode structure comprising a plurality of parallel spaced vertical collecting electrode units so arranged'that eachof said discharge electrode units .isjpositioned-substantially parallel to adjacent collecting electrode units; a suspension means fixed to the upper portion of said precipitating .chamber and connected'to the upper -ends of each collecting electrode unit whereby said units :are vertically suspended 'withinisaid precipitating :chamber; and tensioning and aligning means adapted to hold :each collecting electrode unit under constant tension and to maintain said 'unitsin planes substantially parallel to each other comprising, a firstiset of sheaves fat least one'she'ave being Ifixed to the .lower end of each collecting electrode'unit, a second set of sheaves positioned :b'elow the first 'set, each Isheave being adapted to :receive :a "cable passing ithrough'a sheave of the lfirstset, imeans rigidly holding each sheave of the second set in place and tensioned cable wound in 'snakelike 'fashion, connecting a sheave 'on each electroderunit with acorresponding sheave of the the second set.

2. In an electrical precipitator having a precipitating chamber with a plurality of parallelspaced vertical dlscharge electrode units therein, a collecting electrode structure comprising a plurality of parallel, spaced vertical collecting electrode units so arranged that each of said discharge electrode units is positioned substantially parallel to adjacent collecting electrode units; suspension means fixed to the upper portion of said precipitating chamber, and connected to the upper corners of each collecting electrode unit; shea-vesfixedto thelower corners of each of said collecting electrode units, a pair of spaced structural :members fixed 'to said precipitating :chamber, the longitudinal axes of said members running perpendicular to the planes of said-electrode .units, each member being below correspondinglower corners of said collecting electrode units; sheavesfixed to each :of said members, each of said sheaves positioned below corresponding corners of said discharge electrode units; and tensioned cables wound in snakelike fashion, connecting the sheaves on said electrode units with corresponding sheaves onsaid members.

3. The apparatus of claim 2, each of said collecting electrode units being divided into a plurality of panels, each panel being ilinked to the panel immediately thereabove.

4. In Ian electrical precipitator ihavin'g Ia precipitating chamber with a plurality 'ofparallel, spaced, verticaldischarge electrode units therein, a collecting electrode structure :comprising a .plurality of parallel, spaced, vertical collecting electrode units so arranged that each of said discharge electrode units is positioned substantially parallel to land between adjacent collecting electrode units; each of said collecting electrode units being divided into a plurality of :panels, each "panel being linked to the panel immediately thereabove; za'plurality 'of suspension means [fixed to the 'npper'por tion of :said precipitating chamber'and connected ito'the upper corners'of the uppermost panel of reach collecting electrode unit; sheaves connected to :the :lower corners 'of the lowermost panel ofeachcollecting electrode unit; aipair of spaced structural members fixed to said precipitating "chamber, the longitudinal axes ofsaid members'running'pcrpendicular to the planes :of said electrode units, each member being :ten'sionin'g means.

5. The apparatus of claim 4 in which said cable tensi'oning m'eans comprises a counterweight.

6. The apparatus of claim 4 in which 'said cabletensioning means comprises a spring member.

References Cited. in the filed this patent FOREIGN PATENTS Switzerland Oct. 2, 1922 Great Britain July 7, 1921 

